Ultra-high-strength fiber reinforced concrete has been known which is obtained by mixing reinforcing fibers such as metal fibers or organic fibers into a cement matrix that is obtained by mixing cement and pozzolanic reaction particles (pozzolanic material) into aggregate particles having a largest aggregate particle diameter of 1 to 2 mm (see Patent Documents 1 to 3, etc).
Ultra-high-strength fiber reinforced concrete as described above has such a characteristic that it can secure a certain level of tensile strength and toughness even after development of a crack, by combining fibers having high tensile strength to a cement matrix being dense and having ultra high strength. Specifically, this has been considered to be due to a so-called bridging effect which allows the fibers to cover tensile force for the cement matrix when a crack is developed in the cement matrix as a result of tensile stress acting on the material.
For this reason, unlike conventional reinforced concrete, ultra-high-strength fiber reinforced concrete as described above does not require reinforcement with reinforcing steel bars. Moreover, a concrete structure built using ultra-high-strength fiber reinforced concrete as described above can achieve reduction in the thickness and weight of its components.
Moreover, ultra-high-strength fiber reinforced concrete as described above can achieve significant improvement in durability because the concrete is formed into a denser hydrated body through a hydration reaction process in which the cement matrix is thermally cured.